From ad8a1b558e6c76fb53901956d3c8f29b82a4ccfa Mon Sep 17 00:00:00 2001 From: Shawn Bohrer Date: Tue, 10 Jan 2012 15:07:35 -0800 Subject: [PATCH] fadvise: only initiate writeback for specified range with FADV_DONTNEED Previously POSIX_FADV_DONTNEED would start writeback for the entire file when the bdi was not write congested. This negatively impacts performance if the file contains dirty pages outside of the requested range. This change uses __filemap_fdatawrite_range() to only initiate writeback for the requested range. Signed-off-by: Shawn Bohrer Acked-by: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/fadvise.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/fadvise.c b/mm/fadvise.c index 8d723c9e8b75..469491e0af79 100644 --- a/mm/fadvise.c +++ b/mm/fadvise.c @@ -117,7 +117,8 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice) break; case POSIX_FADV_DONTNEED: if (!bdi_write_congested(mapping->backing_dev_info)) - filemap_flush(mapping); + __filemap_fdatawrite_range(mapping, offset, endbyte, + WB_SYNC_NONE); /* First and last FULL page! */ start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT; -- 2.20.1